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Abstract:

Components of a modular component system are disclosed. A representative
component has, at a first side, a first channel for receiving a connector
and, at a second side, a second channel for receiving a connector. The
first channel extends inwardly from an outer edge of the first side and
in cross-section has a body portion which extends from an opening in the
component in a direction generally parallel to the first side and a head
portion which extends outwardly of the body portion. The second channel
extends inwardly from an outer edge of the second side and in
cross-section has a body portion which extends from an opening in the
component in a direction generally parallel to the second side and a head
portion which extends outwardly of the body portion.

Claims:

1. A component of a modular component system, the component having at a
first side thereof a first channel for receiving a connector and at a
second side thereof a second channel for receiving a connector, wherein:
the first channel extends inwardly of an outer edge of the first side and
in cross-section has a body portion which extends from an opening in the
component in a direction generally parallel to the first side and a head
portion which extends outwardly of the body portion; and the second
channel extends inwardly of an outer edge of the second side and in
cross-section has a body portion which extends from an opening in the
component in a direction generally parallel to the second side and a head
portion which extends outwardly of the body portion, wherein the first
channel extends inwardly to a greater depth than the second channel, such
that a first connector for connecting the component to a complementary
component of the modular component system can be retained in the first
channel and a second connector, which has a smaller width than the first
connector, can be retained in the second channel.

2. A component according to claim 1 wherein the first channel extends
inwardly to twice the depth of the second channel.

3. A component according to claim 1 wherein the first and second channels
are each provided with a threaded bore which extends inwardly into the
component in a direction generally parallel to a side of the component
for receiving a threaded fastener.

4. A component according to claim 2 wherein the first channel is provided
with two threaded bores which extend inwardly into the component in a
direction generally parallel to a side of the component for receiving
threaded fasteners.

5. A component according to claim 1 wherein the first channel and the
second channel are each provided with a threaded bore which extends
inwardly into the component in a direction generally perpendicular to a
side of the component for receiving a threaded fastener.

6. A component according to claim 1 wherein the first and second channels
are generally T-shaped in cross-section.

7. A component according to claim 1 further comprising a first connector
which is removably received in the first channel and a second connector
which is removably received in the second channel.

8. A component according to claim 1 further comprising a foot having a
first side and a second side, the first side being provided with a
threaded aperture and the second side being provided with a through bore
for receiving a threaded fastener.

9. A component according to claim 8 wherein the through bore is enlarged
on an inner face of the second side.

10. A component according to claim 8 wherein the foot is generally
L-shaped.

11. A component according to claim 8 wherein the foot is generally
C-shaped.

12. A component according to claim 1 wherein the component is a piece of
electronic test equipment.

13. A connector for connecting components of a modular system according
to claim 1, the connector having a body portion and a head portion which
extends outwardly of the body portion.

14. A connector according to claim 13 having a through bore which extends
through the connector in a direction generally perpendicular to an upper
surface of the connector.

15. A connector according to claim 14 having two through bores which
extend through the connector in a direction generally perpendicular to an
upper surface of the connector.

16. A connector according to claim 14 wherein each though bore is
countersunk.

17. A connector according to claim 13 wherein the connector is generally
T-shaped in cross-section.

18. A connector according to claim 13 wherein the connector is generally
I-shaped in cross-section.

19. A connector according to claim 18 having through bores which extend
through the connector in a direction generally parallel to an upper
surface of the connector.

20. A fascia for a component of a modular system, the fascia having at a
first side thereof a first channel for receiving a connector and at a
second side thereof a second channel for receiving a connector, wherein:
the first channel extends inwardly of an outer edge of the first side and
in cross-section has a body portion which extends from an opening in the
fascia in a direction generally parallel to the first side and a head
portion which extends outwardly of the body portion; and the second
channel extends inwardly of an outer edge of the second side and in
cross-section has a body portion which extends from an opening in the
fascia in a direction generally parallel to the second side and a head
portion which extends outwardly of the body portion, wherein the first
channel extends inwardly to a greater depth than the second channel, such
that a first connector for connecting the component to a complementary
component of the modular component system can be retained in the first
channel and a second connector, which has a smaller width than the first
connector, can be retained in the second channel.

Description:

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Great Britain Application GB
1016747.6, filed Oct. 5, 2010. This application is incorporated herein by
reference in its entirety.

TECHNICAL FIELD

[0002] The present invention relates to a locking system for modular
component systems, and in particular to a locking system for a system
comprising a plurality of pieces of electronic equipment such as test
instruments.

BACKGROUND

[0003] Electronic equipment such as test instruments is commonly supplied
in cases of standard dimensions. For example, electronic test instruments
are often supplied in cases which are 19 inches wide (full-size) or
half-size cases which are 91/2 inches wide. Such instruments may be
free-standing or may be mounted in a rack of standard dimensions.

[0004] In complex systems, a number of different pieces of electronic
equipment may be required. Typically the different pieces of equipment
are stacked on top of another, or are mounted in a rack.

[0005] It is known for pieces of equipment to be provided with locating
features such as indents in an upper surface which can receive
complementary formations such as projections provided on feet of other
pieces of equipment. This facilitates stacking of the individual pieces
of equipment, but does not inseparably lock the pieces of equipment
together. Thus, systems where a number of individual pieces of equipment
are stacked in this manner can be unstable and vulnerable to toppling if
disturbed, which can lead to damage to the individual pieces of
equipment. Additionally it can be difficult and time consuming to
transport systems of this type, as the individual pieces of equipment may
have to be disengaged from each other and transported separately, since
the equipment may not be stable enough to transport in its stacked
configuration.

[0006] Although it is known for pieces of equipment to be provided with
features to facilitate stacking of the pieces of equipment, no such
features are provided to facilitate attaching known half-size (or
full-size) pieces of equipment together securely in a side by side
configuration for rack-mounting or for free-standing use, and thus in
order to attach such pieces of equipment together in a side-by side
configuration ad-hoc solutions may be employed, which may not be
sufficiently secure.

SUMMARY

[0007] According to a first aspect of the invention there is provided a
component of a modular component system, the component having at a first
side thereof a first channel for receiving a connector and at a second
side thereof a second channel for receiving a connector, wherein the
first channel extends inwardly of an outer edge of the first side and in
cross-section has a body portion which extends from an opening in the
component in a direction generally parallel to the first side and a head
portion which extends outwardly of the body portion; and the second
channel extends inwardly of an outer edge of the second side and in
cross-section has a body portion which extends from an opening in the
component in a direction generally parallel to the second side and a head
portion which extends outwardly of the body portion.

[0008] Components according to the first aspect of the present invention
can quickly and easily be securely locked together, for example in a side
by side or stacked configuration to facilitate movement of the components
or their assembly into larger systems containing many components.

[0009] The first channel may extend inwardly to a greater depth than the
second channel. For example, the first channel may extend inwardly to
twice the depth of the second channel.

[0010] This asymmetric arrangement of the first and second channels
permits standard connectors, which may be supplied with the components,
to be used to lock together any two (or more) components according to the
first aspect of the present invention.

[0011] The first and second channels may each be provided with a threaded
bore which extends inwardly into the component in a direction generally
parallel to a side of the component for receiving a threaded fastener.

[0012] The first channel may be provided with two threaded bores which
extend inwardly into the component in a direction generally parallel to a
side of the component for receiving threaded fasteners.

[0013] The first channel and the second channel may each be provided with
a threaded bore which extends inwardly into the component in a direction
generally perpendicular to a side of the component for receiving a
threaded fastener.

[0014] The use of threaded bores and complementary threaded fasteners
provides a strong and secure means for maintaining connectors in
position, whilst also facilitating the process of locking components
together and unlocking components from each other, since no special tools
are required.

[0015] The first and second channels may be generally T-shaped in
cross-section.

[0016] Channels having a generally T-shaped cross-section have a plurality
of bearing surfaces against which connectors can bear to provide a strong
and secure connection between components which will resist relative
movement of the connected components in different directions.

[0017] The component may further comprise a first connector which is
removably received in the first channel and a second connector which is
removably received in the second channel.

[0018] By providing the connectors in situ in the channels the connectors
are always present when required, thus facilitating the process of
locking components together.

[0019] The component may further comprise a foot having a first side and a
second side, the first side being provided with a threaded aperture and
the second side being provided with a through bore for receiving a
threaded fastener. The foot of the component provides a second means of
locking components together, thereby increasing the stability and
security of a connection between components.

[0020] The through bore may be enlarged on an inner face of the second
said. The foot may be generally L-shaped. Alternatively, the foot may be
generally C-shaped. The component may be, for example, a piece of
electronic test equipment.

[0021] According to a second aspect of the invention there is provided a
connector for connecting components of a modular system according the
first aspect of the invention, the connector having a body portion and a
head portion which extends outwardly of the body portion.

[0022] The connector may have a through bore which extends through the
connector in a direction generally perpendicular to an upper surface of
the connector.

[0023] The connector may have two through bores which extend through the
connector in a direction generally perpendicular to an upper surface of
the connector. Each through bore may be countersunk. The connector may be
generally T-shaped in cross-section. Alternatively, the connect may be
generally I-shaped in cross-section.

[0024] The connector may have through bores which extend through the
connector in a direction generally parallel to an upper surface of the
connector. The through bores may be countersunk.

[0025] According to a third aspect of the invention there is provided a
modular component system comprising a component according to the first
aspect of the invention and a connector according to the second aspect of
the invention.

[0026] According to a fourth aspect of the invention there is provided a
fascia for a component of a modular system, the fascia having at a first
side thereof a first channel for receiving a connect and at a second side
thereof a second channel for receiving a connector, wherein the first
channel extends inwardly of an outer edge of the first side and in
cross-section has a body portion which extends from an opening in the
fascia in a direction generally parallel to the first side and a head
portion which extends outwardly of the body portion; and the second
channel extends inwardly of an outer edge of the second side and in
cross-section has a body portion which extends from an opening in the
fascia in a direction generally parallel to the second side and a head
portion which extends outwardly of the body portion.

[0027] According to a fifth aspect of the invention there is provided a
foot for a component of a modular system, the foot having a first side
and a second side, the first side being provided with a threaded aperture
and the second side being provided with a through bore for receiving a
threaded fastener. The through bore may be enlarged on an inner face of
the second side. The foot may be generally L-shaped. Alternatively, the
foot may be generally C-shaped.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Illustrative aspects in accordance with the invention will be
described in detail with reference to the following figures wherein:

[0029] FIG. 1 is a schematic perspective view of two pieces of electrical
equipment forming image-forming device of the invention.

[0030] FIG. 2 is a side cross-sectional view of a drum subunit provided in
the color laser printer of FIG. 1 on which a developer cartridge is
mounted.

[0031] FIG. 3 is a schematic perspective view of parts of both of the
pieces of electrical equipment shown in FIG. 1.

[0032] FIG. 4 is a schematic perspective view of the parts of the pieces
of electrical equipment shown in FIG. 3, illustrating a step in a process
of locking the pieces of electrical equipment together.

[0033] FIG. 5 is a schematic perspective view of the parts of the pieces
of electrical equipment shown in FIG. 3, illustrating a further step in
the process of locking the pieces of electrical equipment together.

[0034] FIG. 6 is a schematic perspective view of the parts of the pieces
of electrical equipment shown in FIG. 3, showing the pieces of electrical
equipment locked together.

[0035] FIG. 7 is a schematic perspective view of the pieces of electrical
equipment illustrated in FIG. 1 locked together.

[0036] FIG. 8 is a schematic perspective view of the pieces of electrical
equipment shown in FIG. 7 prior to being locked to a further piece of
electrical equipment.

[0037] FIG. 9 is a schematic perspective view of the pieces of electrical
equipment shown in FIG. 8, illustrating a step in a process of locking
the pieces of electrical equipment together.

[0038] FIG. 10 is a schematic perspective view of a schematic perspective
view of parts of the pieces of electrical equipment shown in FIG. 9,
illustrating a further step in the process of locking the pieces of
electrical equipment together.

[0039] FIG. 11 is a schematic perspective view of is a schematic
perspective view of the parts of the pieces of electrical equipment shown
in FIG. 10, showing the pieces of electrical equipment locked together.

[0040] FIG. 12 is a schematic perspective view of the pieces of electrical
equipment shown in FIG. 8, showing the pieces of electrical equipment
locked together.

[0041] FIG. 13 is equipment shown in FIG. 1, illustrating a foot assembly
of the pieces of equipment.

[0042] FIG. 14 is a schematic view perspective of rear parts of the pieces
of electrical equipment shown in FIG. 8, again illustrating a foot
assembly of the pieces of equipment.

DETAILED DESCRIPTION

[0043] Referring first to FIG. 1, a modular component system is shown
generally at 10, and includes first and second components 12, 14. In this
example the components 12, 14 are items of electrical equipment such as
electronic test instruments, but it will be appreciated that the
principles of the present invention are applicable to any modular
component system in which it is desirable to be able to lock components
together securely.

[0044] The first and second components 12, 14, each have a fascia 16,
which, as can be seen in FIG. 2, is provided at a first side 18 with a
first channel 20 extending inwardly of an upper part of the first side 18
for receiving a connector which can be used to lock the component 12, 14
to a complementary component 14, 12, as will be described below. An upper
part of a second side 22 of the fascia is provided with a second channel
24 which extends inwardly of the second side 22, as can be seen in FIG.
3, for receiving a connector which can be used to lock the component 12,
14, to a complementary component 14, 12. As can be seen in FIG. 1,
similar channels are provided in lower parts of the first and second
sides 18, 22 of the fascia 16. These lower channels are inverted versions
of the first and second channels 20, 24 described below and thus will not
be described here in detail.

[0045] The first and second channels 20, 24 are generally T-shaped in
cross-section, having a body portion 26 which extends from an opening in
an upper surface of the fascia 16 in a direction generally parallel to
the side 18, 22 of the fascia 16, and opens into an enlarged head portion
28 which is wider than the body portion 26 and has arms 30, 32 which
extend in opposite directions laterally outwardly of the body portion 26.

[0046] The first channel 20 and the second channel 24 are of different
widths, that is to say the first channel 20 and the second channel 24
extend into the fascia 16 to different depths. In this example the first
channel 20 is twice as wide as the second channel 24, but it is to be
appreciated that any ratio of widths could be employed, provided that one
of the channels 20, 24 is wider than the other.

[0047] The first channel 20 is provided with a threaded bore 34 which
extends inwardly into the component 12, 14 in a direction generally
perpendicular to the side 18 of the fascia 16 and is configured to
receive a threaded fastener such as a screw or bolt to retain a connector
received in the first channel 20, for example when two stacked components
are to be locked together, as will be described below.

[0048] The first channel 20 also has two threaded bores 36, 38, which
extend into the component 12, 14 in a direction generally parallel to the
side 18 of the fascia 16. The bores 36, 38 are configured to receive
threaded fasteners such as screws or bolts to retain a connector or
connectors received in the first channel 20, for example when two
components are to be locked together in a side by side configuration, as
will be described below.

[0049] The second channel 24 is also provided with a threaded bore
extending inwardly into the component 12, 14 in a direction generally
perpendicular to the side 20 of the fascia 16, which bore is configured
to receive a threaded fastener such as a bolt or screw to retain a
connector received in the second channel 24, for example when two stacked
components are to be locked together.

[0050] As the second channel 24 in this example is half the width of the
first channel 20 the second channel 24 is provided with a single threaded
bore which extends into the component 12, 14 in a direction generally
parallel to the side 20 of the fascia 16 and is configured to receive a
threaded fastener such as a bolt or screw to retain a connector received
in the second channel 24, for example when two components are to be
locked together in a side by side configuration.

[0051] Each of the components 12, 14 is provided with a first connector 40
and a second connector 42, which are shown most clearly in FIG. 3.

[0052] The first connector 40 is configured to be received in the first
channel 20, and is generally T-shaped in cross-section. The first
connector 40 has a body portion 44 which terminates in an enlarged head
portion 46 which is wider than the body portion 44 and has arms 48, 50
which extend in opposite directions laterally outwardly of the body
portion 44.

[0053] The first connector 40 is provided with two countersunk bores 52,
54 which extend through the first connector 40 in a direction generally
perpendicular to an upper surface 56 of the first connector 40, and are
positioned such that when the first connector 20 is received in the first
channel 20 the bores 52, 54 align with the bores 36, 38 of the first
channel 20 such that threaded bolts or screws 58, 60 can be passed
through the first connector 40 to be received in the threaded bores 36,
38 of the first connector 20 to retain the first connector 40 in place
within the first channel 20.

[0054] The second connector 42 is configured to be received in the second
channel 24, and is thus half of the width of the first connector 40. Like
the first connector 40 the second connector 42 is generally T-shaped in
cross-section, having a body portion 62 which terminates in an enlarged
head portion 64 which is wider than the body portion 62 and has arms 66,
68 which extend laterally outwardly of the body portion 60 in opposite
directions.

[0055] As the second connector 42 is half the width of the first connector
40, it is provided with a single countersunk bore 70 which extends
through the second connector 42 in a direction generally perpendicular to
an upper surface 72 of the second connector 42 and is positioned such
that when the second connector 42 is received in the second channel 24
the bore 68 aligns with the bore of the second channel 24 such that a
threaded bolt or screw 74 can be passed through the second connector 42
to be received in the threaded bore of the second channel 24 to retain
the second connector 42 in place within the second channel 24.

[0056] The bores in the first and second connectors 40, 42 are countersunk
so that when the bolts or screws 58, 60, 74 are received in the bores of
the first and second channels 20, 24 to retain the first and second
connectors 40, 42 in the first and second channels 20, 24 the heads of
the bolts or screws 58, 60, 74 lie flush with the upper surfaces 56, 72
of the first and second connectors 40, 42. The first and second
connectors 40, 42 are shaped and dimensioned such that when they are
received in the first and second channels 20, 24 their upper surfaces 56,
72 lie flush with or just below a surface of the fascia 16 so as to
produce a smooth finish.

[0057] When the components 12, 14 are to be used in isolation the first
and second connectors 40, 42 are received in the first and second
channels 20, 24 and retained in place by the bolts or screws 58, 60, 74.
The first and second connectors 40, 42 are moved when two components 12,
14 are to be locked together in a side by side configuration, as will be
described below with reference to FIGS. 1-7.

[0058] As is shown in FIG. 1, a first step in the process of locking the
first and second components 12, 14 together in a side by side
configuration is the removal of the first connector 40 from the first
channel 20 of the second component 14, by removing the bolts or screws
58, 60 to allow the first connector 40 to slide out of the first channel
20 of the second component, as shown in FIG. 2.

[0059] The second connector 42 of the first component 12 is then removed
from the second channel 24 of the first component 12 in the same manner,
as shown in FIG. 3.

[0060] The second connector 42 of the first component 12 is then inserted
into the first channel 20 of the second component 14 and secured in place
using one of the bolts or screws 58, 60, 74, as shown in FIG. 4. As the
second connector 42 is half the width of the first channel 20, it does
not occupy the whole of the first channel 20.

[0061] The first connector 40 is then inserted into the first channel 20
of the second component 14. As the second connector 42 is already
installed in the first channel 20, half of the first connector 40
protrudes outwardly of the first channel 20 of the second component 14,
as is shown in FIG. 5. The first connector 40 is secured in place in the
first channel 20 of the second component 14 by one of the bolts or screws
58, 60, 74, which is passed through the countersunk bore 54 of the first
connector 40 and engages with the complementary bore 36 of the first
channel 20.

[0062] The first component 12 is then brought into engagement with the
second component 14 such that the protruding half of the first connector
40 is received in the second channel 24 of the first component 12, and
the first connector 40 is secured in place by one of the bolts or screws
58, 60, 74, which passes through the countersunk bore 52 of the first
connector 40 and engages with the complementary bore of the second
channel 24 of the first component. Thus, the first and second components
12, 14 are locked together, as shown in FIGS. 6 and 7, such that they can
be manipulated as a single component.

[0063] The use of threaded fasteners such as bolts or screws 58, 60, 74 to
secure the first and second connectors 40, 42 in the first and second
channels 20, 24 of the components 14, 12 facilitates the process of
locking the components 12, 14 together, as no special tools are required
to complete the process.

[0064] It is to be appreciated that the locking process has been described
here by reference to the connectors 40, 42 and channels 20, 24 of the
upper parts of the first and second sides 18, 22 of the fascias 16 of the
first and second components 12, 14, but that the same process applies to
the connectors and channels in the lower parts of the fascias 16 of the
first and second components 12, 14. Moreover, although the first and
second components 12, 14 can be locked together satisfactorily using only
the upper or lower connectors and channels, a more secure connection is
provided if the upper and lower connectors and channels are both used to
lock the first and second components together.

[0065] As well as the side by side configuration described above,
components can also be securely stacked together by means of alternative
connectors, as will be described below with reference to FIGS. 8 to 12.

[0066] FIG. 8 shows first and second components 12, 14 which have been
locked together as described above. These components are to be locked to
a third component 80 in a stacked configuration. Like the first and
second components 12, 14, the third component has a fascia 16 which is
provided at a first side 18 with upper and lower first channels 20 and at
a second side 22 with upper and lower second channels 24. The upper and
lower first and second channels 20, 24 of the third component 80 have the
same shape and configuration as those of the first and second components
12, 14.

[0067] In order to securely lock the first and second components 12, 14 to
the third component in the stacked configuration shown in FIG. 10 third
and fourth connectors 82, 84 are provided. The third connector 84 is
generally I-shaped in cross section, having a central body portion which
is provided at each end with a head portion from which arms extend
laterally outwardly in opposite directions.

[0068] The third connector 82 may be regarded as two of the T-shaped first
connectors 40 whose body portions 44 are connected at their free ends to
form the I-shaped third connector 82. Thus, the third connector 82 is
configured to be received in the first channel 20 of the components 12,
14, 80 such that when so received half of the body portion and one of the
head portions are received in the first channel 20 whilst the other half
of the body portion and the other head portion protrude outwardly of the
first channel 20 in a direction generally perpendicular to the direction
of the first channel 20.

[0069] Similarly, the fourth connector 84 may be regarded as being two of
the T-shaped second connectors 42 whose body portions 62 are connected at
their free ends to form an I-shaped connector 84. Thus, the fourth
connector 82 is configured to be received in the second channel 24 of the
components 12, 14, 80 such that when so received half of the body portion
and one of the head portions are received in the second channel 24 whilst
the other half of the body portion and the other head portion protrude
outwardly of the second channel 24 in a direction generally perpendicular
to the direction of the second channel 24.

[0070] As can be seen from FIGS. 8 and 9, the fourth connector 84 is half
the width of the third connector 82. Thus, when the third connector 82 is
received in the first channel 20 of a component 12, 14, 80, its outer
edge lies flush with the outer edge of the first side 18 of the component
12, 14, 80, whilst when the fourth connector 84 is received in the second
channel 24 of a component 12, 14, 80 its outer edge lies flush with the
outer edge of the second side 22 of the component 12, 14, 80.

[0071] To connect the first and second components 12, 14 to the third
component 80 in the stacked configuration shown in FIGS. 9 and 12, the
first connector 40 is removed from the lower first channel 20 of the
second component 14, and the second connector 42 is removed from the
lower second channel 24 of the first component 12. The first and second
connectors 40, 42 are also removed from the upper first and second
channels 20, 24 of the third component 80.

[0072] The first and second components 12, 14 are then positioned on top
of the third component 80, as shown in FIG. 9, such that the lower first
channel 20 of the second component 14 and the upper first channel 20 of
the third component form a first generally I-shaped channel, whilst the
lower second channel 24 of the first component 12 and the upper second
channel 24 of the third component 80 form a second generally I-shaped
channel. As the second generally I-shaped channel is formed by the two
second channels 24, its depth is half that of the first generally
I-shaped channel.

[0073] The third connector 82 is inserted into the first generally
I-shaped channel and threaded bolts or screws 86 are passed through
countersunk bores 88 in the two head portions to engage with the
complementary bores 34 in the first channels 20 of the second component
14 and the third component 80 to lock the components 14, 80 together at
their first sides 18, as is shown in FIGS. 10 and 11. Similarly, the
fourth connector 84 is inserted into the second generally I-shaped
channel and threaded bolts or screws 90 are passed through countersunk
bores in the two head portions to engage with the complementary bores in
the second channels 24 of the first component 12 and the third component
80 to lock the components 12, 80 together at their second sides 22.

[0074] The connectors 40, 42, 82, 84 described above are generally T- or
I-shaped in cross-section, as this shape provides a strong and stable
connection, since a plurality of bearing faces of the connectors 40, 42,
82, 84 are in contact with the channels 20, 24, which impedes relative
movement between the components 12, 14, 80 which are locked together.
However, it will be appreciated that alternative configurations of
connectors and channels having in cross-section a body portion and a head
portion which extends outwardly of the body portion are equally suitable
for the purpose of securely locking components together. For example, the
channels and connectors could be substantially L-shaped, C-shaped or
keyhole shaped in cross-section, and thus the invention is not limited to
a particular cross-sectional shape of channel and connector.

[0075] The first and second components 12, 14 are also provided with feet
100, which, as shown in FIG. 13, are mounted on rear corners of the first
and second components 12, 14, and provide an additional means of locking
the first and second components 12, 14 together, as will be described
below.

[0076] As can be seen in FIG. 13, the feet 100 are generally L-shaped,
having a first side 102 and a second side 104 which are of a generally
similar size and shape and which are mounted generally at right angles
with respect to one another.

[0077] A bore is provided in the first side 102 and contains a captive nut
106, whilst a through bore 108 is provided in the second side 104. The
through bore 108 is enlarged on an inner face 110 of the second side 104
such that a head of a threaded fastener such as a bolt or screw 112 can
be received in the enlarged portion of the through bore 108.

[0078] The captive nut 106 and the through bore 108 are equidistant from
the angle of the L-shaped foot 100 such that when an outer face of the
first side 102 of a foot 100 of the first component 12 abuts an outer
face of the second side 104 of a foot 100 of the second component 14, as
shown in FIG. 13, the through bore 108 and the captive nut 106 are
aligned such that a threaded bolt or screw 112 can be passed through the
through bore 108 to engage with the captive nut 106 to lock the first
component 12 and the second component 14 together, with a head of the
bolt or screw 112 being received in the enlarged portion of the through
bore 108 on the inner face 110 of the second side 104 of the foot 100.

[0079] It will be appreciated that all of the feet 100 of the first and
second components 12, 14 are identical, and thus are mounted on the rear
corners of the components 12, 14 in different orientations. This ensures
that when the components are to be locked together in the side by side
configuration shown in FIG. 13, the sides 102, 104 of the feet 100 of the
first component 12 abut against complementary sides 104, 102 of the feet
of the second component 14 such that a threaded bolt or screw 112 can be
used to lock the feet 100 of the first and second components 12, 14
together.

[0080] FIG. 14 shows an alternative foot 120 which may be used for
shallower components such as the third component 80, and can be used to
lock such components to other components 12, 14.

[0081] As can be seen from FIG. 14, the feet 120 of the third component 80
are generally C-shaped, having a central portion 122 from which upper and
lower arm portions 124, 126 extend generally perpendicularly. The upper
arm portion 124 is provided with a bore containing a captive nut, whilst
the lower arm portion 126 is provided with a through bore 128 which is
enlarged on an inner face 130 of the lower arm portion 126. As is shown
in FIG. 14, the captive nut is positioned such that when the third
component is arranged in a stacked configuration with other components
12, 14, the captive nut aligns with a through bore 108 of a foot 100 of
another component 14, such that a threaded bolt or screw 132 can be
passed through the trough bore 108 to engage with the captive nut of the
foot 120 of the third component 80 to lock the third component 80 to the
component 14.

[0082] The third component 80 is supplied with a further foot at its
opposite side. The further foot is identical to the foot 120, and is thus
mounted to the third component 80 in an orientation which is offset by
180 degrees from that of the foot 120, such that the arm portion
containing the captive nut is at a lower end of the foot and the arm
portion containing the through bore is at an upper end of the foot. This
use of a single design of foot 120 in different orientations ensures that
when components 80, 12, 14 are to be locked together in the stacked
configuration shown in FIG. 14 a through bore 128 of the foot 120 will
always align with a captive nut 106 of a foot 100 at one side of the
component 80, whilst at the other side of the component 80 a captive nut
of a foot 120 will align with a through bore 108 of a foot 100, such that
the components 80, 12, 14 can be securely locked together.